refactor catalog api endpoints

pgorecki · pgorecki · commit c1d24e267dd7 · 2022-12-07T20:11:59.000+01:00
diff --git a/pyproject.toml b/pyproject.toml
@@ -24,6 +24,7 @@ psycopg2-binary = "^2.9.2"
 freezegun = "^1.1.0"
 SQLAlchemy-Utils = "^0.38.3"
 pre-commit = "^2.20.0"
+click = "8.0.4"
 
 [tool.poetry.dev-dependencies]
 poethepoet = "^0.10.0"
diff --git a/src/api/main.py b/src/api/main.py
@@ -23,7 +23,6 @@
 app.include_router(iam.router)
 app.container = container
 
-
 logger.info("using db engine %s" % str(container.engine()))
 
 
diff --git a/src/api/models.py b/src/api/models.py
@@ -14,11 +14,17 @@ def fake_user(cls):
 
 class ListingWriteModel(BaseModel):
     title: str
+    description: str
+    ask_price_amount: float
+    ask_price_currency: str = "USD"
 
 
 class ListingReadModel(BaseModel):
     id: UUID
     title: str = ""
+    description: str
+    ask_price_amount: float
+    ask_price_currency: str
 
 
 class ListingIndexModel(BaseModel):
diff --git a/src/api/routers/catalog.py b/src/api/routers/catalog.py
@@ -3,12 +3,13 @@
 from api.models import ListingIndexModel, ListingReadModel, ListingWriteModel
 from api.shared import dependency
 from config.container import Container, inject
+from modules.catalog import CatalogModule
 from modules.catalog.application.command.create_listing_draft import (
     CreateListingDraftCommand,
 )
 from modules.catalog.application.query.get_all_listings import GetAllListings
 from modules.catalog.application.query.get_listing_details import GetListingDetails
-from modules.catalog.module import CatalogModule
+from seedwork.domain.value_objects import Money
 from seedwork.infrastructure.request_context import request_context
 
 router = APIRouter()
@@ -23,21 +24,24 @@ async def get_all_listings(
     Shows all published listings in the catalog
     """
     query = GetAllListings()
-    query_result = module.execute_query(query)
-    return dict(data=query_result.result)
+    with module.unit_of_work():
+        query_result = module.execute_query(query)
+        return dict(data=query_result.result)
 
 
 @router.get("/catalog/{listing_id}", tags=["catalog"], response_model=ListingReadModel)
 @inject
 async def get_listing_details(
-    listing_id, module: CatalogModule = dependency(Container.catalog_module)
+    listing_id,
+    module: CatalogModule = dependency(Container.catalog_module),
 ):
     """
     Shows listing details
     """
     query = GetListingDetails(listing_id=listing_id)
-    query_result = module.execute_query(query)
-    return query_result.result
+    with module.unit_of_work():
+        query_result = module.execute_query(query)
+        return query_result.result
 
 
 @router.post(
@@ -51,19 +55,21 @@ async def create_listing(
     """
     Creates a new listing.
     """
-    command_result = module.execute_command(
-        CreateListingDraftCommand(
-            title=request_body.title,
-            description="",
-            price=1,
-            seller_id=request_context.current_user.id,
-        )
+    command = CreateListingDraftCommand(
+        title=request_body.title,
+        description=request_body.description,
+        ask_price=Money(request_body.ask_price_amount, request_body.ask_price_currency),
+        seller_id=request_context.current_user.id,
     )
+    with module.unit_of_work():
+        command_result = module.execute_command(command)
+
+        query = GetListingDetails(listing_id=command_result.result)
+        query_result = module.execute_query(query)
+        return query_result.result
 
-    query = GetListingDetails(listing_id=command_result.result)
-    query_result = module.execute_query(query)
-    return query_result.result
 
-    # TODO: for now we return just the id, but in the future we should return
-    # a representation of a newly created listing resource
-    return {"id": result.id}
+#
+#     # TODO: for now we return just the id, but in the future we should return
+#     # a representation of a newly created listing resource
+#     return {"id": result.id}
diff --git a/src/config/container.py b/src/config/container.py
@@ -3,6 +3,7 @@
 from sqlalchemy import create_engine
 
 from modules.catalog import CatalogModule
+from modules.iam import IamModule
 
 
 def _default(val):
@@ -60,3 +61,8 @@ class Container(containers.DeclarativeContainer):
         CatalogModule,
         engine=engine,
     )
+
+    iam_module = providers.Factory(
+        IamModule,
+        engine=engine,
+    )
diff --git a/src/modules/catalog/__init__.py b/src/modules/catalog/__init__.py
@@ -2,6 +2,7 @@
 from contextlib import contextmanager
 from contextvars import ContextVar
 from dataclasses import dataclass
+from typing import Any
 
 from sqlalchemy.orm import Session
 
@@ -44,6 +45,7 @@ def get_arg(name, kwargs1, kwargs2):
 
 @dataclass
 class UnitOfWork:
+    module: Any  # FIXME: type
     db_session: Session
     correlation_id: uuid.UUID
     listing_repository: ListingRepository
@@ -64,6 +66,7 @@ def unit_of_work(self, **kwargs):
         db_session = None
         with Session(engine) as db_session:
             uow = UnitOfWork(
+                module=self,
                 correlation_id=correlation_id,
                 db_session=db_session,
                 listing_repository=PostgresJsonListingRepository(db_session=db_session),
@@ -96,7 +99,19 @@ def execute_command(self, command):
                 if isinstance(attr, param_type):
                     kwargs[param_name] = attr
 
-        return handler(command=command, **kwargs)
+        return handler(command, **kwargs)
+
+    def execute_query(self, query):
+        query_class = type(query)
+        handler = registry.get_query_handler_for(query_class)
+        kwargs = registry.get_query_handler_parameters_for(query_class)
+
+        for param_name, param_type in kwargs.items():
+            for attr in self.uow.__dict__.values():
+                if isinstance(attr, param_type):
+                    kwargs[param_name] = attr
+
+        return handler(query, **kwargs)
 
     @property
     def uow(self) -> UnitOfWork:
diff --git a/src/modules/catalog/application/query/get_all_listings.py b/src/modules/catalog/application/query/get_all_listings.py
@@ -1,18 +1,24 @@
-from modules.catalog.domain.repositories import ListingRepository
+from sqlalchemy.orm import Session
+
+from modules.catalog.application.query.model_mappers import map_listing_model_to_dao
+from modules.catalog.infrastructure.listing_repository import ListingModel
 from seedwork.application.decorators import query_handler
 from seedwork.application.queries import Query
 from seedwork.application.query_handlers import QueryResult
 
 
 class GetAllListings(Query):
+    """This query does not need any parameters"""
+
     ...
 
 
 @query_handler
 def get_all_listings(
-    query: GetAllListings, listing_repository: ListingRepository
+    query: GetAllListings,
+    session: Session,
 ) -> QueryResult:
-    queryset = listing_repository.session.query(listing_repository.model)
-    result = [dict(id=row.id, **row.data) for row in queryset.all()]
+    queryset = session.query(ListingModel)
+    result = [map_listing_model_to_dao(row) for row in queryset.all()]
     # TODO: add error handling
     return QueryResult.ok(result)
diff --git a/src/modules/catalog/application/query/get_listing_details.py b/src/modules/catalog/application/query/get_listing_details.py
@@ -1,4 +1,7 @@
-from modules.catalog.domain.repositories import ListingRepository
+from sqlalchemy.orm import Session
+
+from modules.catalog.application.query.model_mappers import map_listing_model_to_dao
+from modules.catalog.infrastructure.listing_repository import ListingModel
 from seedwork.application.decorators import query_handler
 from seedwork.application.queries import Query
 from seedwork.application.query_handlers import QueryResult
@@ -10,11 +13,7 @@ class GetListingDetails(Query):
 
 
 @query_handler
-def get_listing_details(
-    query: GetListingDetails, listing_repository: ListingRepository
-) -> QueryResult:
-    queryset = listing_repository.session.query(listing_repository.model).filter_by(
-        id=query.listing_id
-    )
-    result = [dict(id=row.id, **row.data) for row in queryset.all()][0]
+def get_listing_details(query: GetListingDetails, session: Session) -> QueryResult:
+    queryset = session.query(ListingModel).filter_by(id=query.listing_id)
+    result = [map_listing_model_to_dao(row) for row in queryset.all()][0]
     return QueryResult.ok(result)
diff --git a/src/modules/catalog/application/query/get_listings_of_seller.py b/src/modules/catalog/application/query/get_listings_of_seller.py
@@ -1,4 +1,6 @@
-from modules.catalog.domain.repositories import ListingRepository
+from sqlalchemy.orm import Session
+
+from modules.catalog.infrastructure.listing_repository import ListingModel
 from seedwork.application.decorators import query_handler
 from seedwork.application.queries import Query
 from seedwork.application.query_handlers import QueryResult
@@ -10,10 +12,9 @@ class GetListingsOfSeller(Query):
 
 
 @query_handler
-def get_listings_of_seller(
-    query: GetListingsOfSeller, listing_repository: ListingRepository
-) -> QueryResult:
-    queryset = listing_repository.session.query(listing_repository.model)  # .filter(
+def get_listings_of_seller(query: GetListingsOfSeller, session: Session) -> QueryResult:
+    # FIXME: use seller_id to filter out listings
+    queryset = session.query(ListingModel)  # .filter(
     #     listing_repository.model.data['seller'].astext.cast(UUID) == query.seller_id
     # )
     result = [dict(id=row.id, **row.data) for row in queryset.all()]
diff --git a/src/modules/catalog/application/query/model_mappers.py b/src/modules/catalog/application/query/model_mappers.py
@@ -0,0 +1,14 @@
+from modules.catalog.infrastructure.listing_repository import ListingModel
+
+
+def map_listing_model_to_dao(instance: ListingModel):
+    """maps ListingModel to a data access object (a dictionary)"""
+    data = instance.data
+    return dict(
+        id=instance.id,
+        title=data["title"],
+        description=data["description"],
+        ask_price_amount=data["ask_price"]["amount"],
+        ask_price_currency=data["ask_price"]["currency"],
+        seller_id=data["seller_id"],
+    )
diff --git a/src/modules/iam/__init__.py b/src/modules/iam/__init__.py
@@ -0,0 +1,2 @@
+class IamModule:
+    pass
diff --git a/src/seedwork/application/decorators.py b/src/seedwork/application/decorators.py
@@ -16,6 +16,7 @@
 class Registry:
     def __init__(self):
         self.command_handlers = {}
+        self.query_handlers = {}
 
     def register_command_handler(
         self, command_class: type[Command], handler: Callable, handler_parameters
@@ -32,6 +33,21 @@ def get_command_handler_for(self, command_class) -> Callable:
     def get_command_handler_parameters_for(self, command_class) -> Callable:
         return self.command_handlers[command_class][1].copy()
 
+    def register_query_handler(
+        self, query_class: type[Query], handler: Callable, handler_parameters
+    ):
+        logger.info(f"registering query handler for {query_class} as {handler}")
+        self.query_handlers[query_class] = (handler, handler_parameters)
+
+    def get_query_handler_for(self, query_class) -> Callable:
+        assert (
+            query_class in self.query_handlers
+        ), f"handler for {query_class} not registered"
+        return self.query_handlers[query_class][0]
+
+    def get_query_handler_parameters_for(self, query_class) -> Callable:
+        return self.query_handlers[query_class][1].copy()
+
     def clear(self):
         self.command_handlers.clear()
 
@@ -91,4 +107,13 @@ def decorator(*args, **kwargs):
         except BusinessRuleValidationException as e:
             return QueryResult.failed("Business rule validation error", exception=e)
 
+    handler_signature = signature(fn)
+    kwargs_iterator = iter(handler_signature.parameters.items())
+    _, first_param = next(kwargs_iterator)
+    query_class = first_param.annotation
+    assert issubclass(query_class, Query), "The first parameter must be of type Command"
+    handler_parameters = {}
+    for name, param in kwargs_iterator:
+        handler_parameters[name] = param.annotation
+    registry.register_query_handler(query_class, decorator, handler_parameters)
     return decorator
diff --git a/src/seedwork/tests/application/test_decorators.py b/src/seedwork/tests/application/test_decorators.py
@@ -2,6 +2,7 @@
 
 from seedwork.application.commands import Command
 from seedwork.application.decorators import command_handler, registry
+from seedwork.application.queries import Query
 
 
 def test_command_handler_decorator_registers_command_handler():
@@ -35,3 +36,18 @@ def foo_command_handler(command: BarCommand):
         ...
 
     assert FooCommand not in registry.command_handlers
+
+
+def test_query_handler_decorator_registers_query_handler():
+    registry.clear()
+
+    @dataclass
+    class FooQuery(Query):
+        ...
+
+    @command_handler
+    def foo_query_handler(command: FooQuery):
+        ...
+
+    assert registry.get_command_handler_for(FooQuery) == foo_query_handler
+    assert registry.get_command_handler_parameters_for(FooQuery) == {}
